I disagree with the above statement. The RV is a vehicle and almost every state treats it like a vehicle, not a DOMICILE. Which means, if you have got a loaded handgun you better have a CCW for that state, and in some states they do can't a loaded mag as a loaded firearm.
Best bet is always to check the state laws where you will be traveling, because as someone else said, there isn't a "Do it all" answer.